Bottom saw blade height adjustment

ABSTRACT

The invention provides a device for use in the extraction of bottles or the like from cartons travelling in a stream on a conveyor, each carton having a bottom wall and associated side walls. The device has a saw blade adapted to extend across the conveyor to cut the associated side walls just above the base which is thereby severed. The saw blade is vertically adjustable so as to accommodate cartons having bases of different thickness&#39; and thereby ensure avoidance of damage to the bottles sitting on said bottom wall. A sensor positioned upstream of said blade determines the vertical position required for each passing carton and transmits a signal which results in the blade being positioned as required.

FIELD OF THE INVENTION

[0001] The present invention relates to the recycling field and more specifically to the handling of empty bottles returned in their originally provided carton for re-use or recycling. In particular, the invention is concerned with separating in a continuous manner empty bottles from cardboard cartons containing same.

BACKGROUND OF THE INVENTION

[0002] In the beverage industry, particularly the brewing industry, there are certain advantages to the use of refillable primary containers, such as glass bottles, in preference over cans or other non-refillable containers. Refillable bottles are ecologically friendly and enjoy a very high return rate because there is an incentive for consumers to return the bottles—namely, to obtain a mandatory refundable deposit on the bottles. It may be noted however, that the non-refillable primary containers are frequently returnable for recycling as scrap metal, glass etc. and separation of those containers from their package must also be effected.

[0003] A disadvantage of using refillable bottles, from the standpoint of the bottler, is that refillable bottles can be difficult or awkward and expensive to handle. They must be separated from the packaging in which they have been returned, labels removed, cleaned, and sterilized before they are re-used. There are numerous machines available for many of the required activities e.g. the cleaning and sterilizing steps of the bottles. Design of a machine at reasonable cost in these areas of handling can be simplified somewhat by the standardized sizes and shapes of bottles.

[0004] It is more difficult, however, to automate those steps of the bottle handling process dealing with removal of the bottles from their associated packaging which, obviously must take place before individual bottles can be dealt with. Most bottles are returned to a facility in the packaging in which the bottles were sold to the consumer. In Canada, beer bottles are packaged most frequently in six, twelve and twenty-four bottle cartons, the twelve frequently having a three bottle by four bottle configuration, and the twenty-four having a six bottle by four bottle configuration. The twelve and twenty-four bottle cartons are generally made from cardboard, the former usually paperboard and the latter, the thicker corrugated cardboard.

[0005] It will be appreciated that a carton full of empty bottles when returned may be wet, bent, ripped, folded in an unusual manner, have missing parts, filled with debris or broken glass, or otherwise not in an ideal condition for handling. The inconsistent condition of returned cartons makes them difficult to process automatically, but because of the low value of their contents, they must be processed very quickly and efficiently to keep costs at an acceptable level. Furthermore, it is common for the brewer to receive cartons of various sizes together on the same pallet. For example, a layer of 24's will sit on a layer of 12's.

[0006] Heretofore, one of the most efficient ways of removing bottles from returned cardboard cartons has been to use a band saw to cut across a carton near its base, thereby severing the base from the walls of a carton and then hand stripping the loose walls of the carton then in the form of a sleeve—from over the bottles. A problem with this method is that the saw blade, upon initially contacting the case side wall, a bottle inside the carton higher than is optimally desirable if bottle damage is to be avoided.

[0007] A further problem centres around the fact that the heel of the bottle is made of relatively thick glass, but the main body above the heel is not and is therefore, more susceptible to damage if struck by a saw blade. It is therefore very important that the saw blade is accurately positioned above the conveyor surface to ensure that it does not strike bottles in the carton above the heel. Moreover, the various types and sizes of carton may be made of different materials which usually do not have the same thickness. For example, 6-packs (6-packs have one layer but the returns are in trays) and 12-packs (12-packs have only one layer for its bottom) are usually made of relatively thin chipboard whereas 24-packs are made of thicker corrugated board (24-packs have two layers of board for its bottom). Consequently, the bottles in different sized cartons moving on the same conveyor are spaced from the conveyor surface different amounts. Unfortunately a mixture of carton sizes are returned together to the brewer and it is not really feasible to sort these prior to them being carried to the saw device for treatment. In the circumstances, if continuous operation is to be maintained, a compromise or average position above the conveyor surface is usually chosen which can cause problems of the type discussed above.

[0008] Canadian Patent No. 2,216,395 provides a method of cutting open the beer carton to expose the neck of the beer bottles in the carton, so that the bottles can be accessed by in-line equipment, rather than by overhead equipment. The patent teaches a complex device using multiple rotary saw blades to cut through the side walls of opposed sides of cartons from end to end as said cases are moved past said saws and, subsequently, carton orienting means are situated downstream of said saws to present the uncut side walls of said cartons towards the sides of said conveyor; and further saws are arranged at the sides of said conveyor belt to cut through the remaining two side walls of said cartons from end to end as said cases are moved past the further saws to sever the tops and a portion of said side wall. This is obviously a complex and expensive system requiring significant maintenance.

[0009] It is an objective of the present invention to provide a method and apparatus for use in a system for continuously separating bottles from cartons in which they are enclosed thereby allowing same to be economically re-used or recycled.

SUMMARY OF THE INVENTION

[0010] This is achieved by providing a saw station to which the filled cartons are lead and at which, a saw severs the base or bottom by cutting through a lower portion of the carton walls to which the base is attached. The saw blade is arranged to cut the walls just above the surface of the base or bottom on which the bottles rest thus minimizing contact between the saw blade and the bottles. An important feature of the invention is that the height between the saw blade and the support surface or table on which the filled cartons are sitting when treated be variable at least at the place of contact between the carton and the saw blade so that the saw blade can be maintained at an optimum position to minimize adverse contact with the bottles despite variances in thickness of the material of the bases of the cartons arriving at the station. These variances of course, result in the distance the base of the bottle is from the support surface also varying and increased risk of the blade contacting and chipping etc. the bottle higher up or above the heel. The adjustment of the vertical distance between the saw blade and at least the edge of the table adjacent the saw blade can be achieved by arranging for the saw blade or the table edge, or both, to be vertically moveable relative to the other. It is preferred that the table edge be movable relative to the saw blade. Moreover, it is most preferred that the relative movement to achieve optimum by aligned cutting action be made automatically to accommodate each carton as it enters the saw station. The desired adjustment may be effected mechanically or by providing means, such as a pneumatic or hydraulic simple piston and cylinder arrangement, to lift or lower the table vertically toward or away the saw blade, or vice versa, which means may be operated by hand but preferably automatically. In a preferred aspect of the invention, it is activated in response to a signal from a sensor (sensors) located in an inspection station upstream from the saw station. The sensor (sensors) is (are) programmed to differentiate between (24's and 12's using the handle opening of the 12-packs) cartons having bases or bottoms of differing thickness travelling on a feed conveyor; evaluate the table setting for each identified container based on preprogrammed table height criteria and, following a delay calculated to allow each specific carton to reach the saw station and thereby be located on the table, make any required height adjustment. In this way, it is ensured that the vertical height or distance between the saw blade and the adjacent downstream edge of the table is optimum for the thickness of the base of the specific container then located at the saw station. The carton at the station is generally urged through the station by the following carton.

[0011] Preferably the saw blade is a band saw blade operating in a continuous loop manner although other types, such as a reciprocating band saw could be used. Also, the blade may be oriented at an angle to the longitudinal axis of the station and carton support so that butting of the carton wall commences initially at one corner of the carton and then progresses across the carton. This provides a cleaner cut especially at rapid carton treatment rates.

[0012] It is also preferred to provide a slot or opening below the saw blade through which the severed base can enter and be removed. Following exiting the saw station, the carton walls and top, if any, are readily removed manually or by mechanical means, such as gripping claws or suction devices.

[0013] In this specification, removal of bottles from a carton and removal of a carton from enclosed bottles are considered the same.

[0014] The present invention will be described with reference to the accompanying drawings which show a preferred embodiment thereof and in which:

[0015]FIG. 1 is an angled perspective showing in part a saw station of the present invention;

[0016]FIG. 2 is a similar view to FIG. 1 but showing the saw blade in its raised position;

[0017]FIG. 3 is a top perspective of the upstream conveyor delivering bottle-filled cartons to the saw station;

[0018]FIG. 4 is a view from below of part the piston—cylinder arrangement which provides the vertical movement of the carton table saw arrangement;

[0019]FIG. 5 is a part cross-section through a carton and one enclosed bottle located on a carton support at a saw station of the present invention.

[0020] In the following, the bottle recovery line is set up to handle a mix of 12-packs and 24-packs (and 6-packs in trays) of empty beer bottles.

[0021] In the drawings, a saw station, generally designated 10 and shown in detail in FIGS. 1, 2 and 3, is served by an upstream plate conveyor 12 which brings cartons 14 and 15 to the station 10 and downstream or exit conveyor 16 which carries away bottles enclosed within a carton, the bottom of which has been severed and removed at the station 10. The station 10 effectively connects conveyors 12 and 16 and comprises a carton supporting-table 18 having a downstream edge 19 and, adjacent thereto, saw blade 20, all but the cutting edge 22 thereof being located under dead plate 24 which has an upstream edge 26 which restricts blade 20 from significant vertical movement. Between cutting edge 22 and edge 26 of plate 24 is a slot 28. It should be noted, please refer FIG. 5 that blade cutting edge 22 is not only laterally spaced from plate edge 26 but also vertically spaced, a height or distance “h” calculated to ensure that cutting edge 22 contacts the side wall 30 of a carton 32 arriving at table 18 at the correct pre-determined height. The objective is to minimize saw contact with the bottle 33, specifically the bottle wall 34, radially outermost bulge 36 formed at the join of the bottle wall 34 and bottle base 38—refer FIG. 5—It may also be noted that carton table 18 has a length less than the length of the carton 30 and consequently, the carton (not shown) following carton 30 which is on plate 24 continues to move under the influence of conveyor 12 to smoothly urge carton 30 which is on the plate, through the station 10.

[0022] The edge 22 of saw blade 20 is preferably angled at about 20° to the longitudinal axis of table 18. This ensures that severing of the container walls commences at one relatively small locality and then progresses across the carton front or end wall 32 simultaneously with a side wall. This assists in providing a clean cut especially when handling cartons at higher speeds.

[0023] Included in FIGS. 1 and 2 for illustrative purposes is a rectangular member 37 which has a slot 39 cut in at one end. This shows the two height settings for the blade 20 in this embodiment. FIG. 1, the blade 20 is at its lower position where it can optimally handle thin bottomed 12-packs and in FIG. 2, blade 20 is at its elevated position to better handle thicker based 24-packs. Turning to FIG. 3, an upstream section of conveyor 12, is provided with optical sensors 40 and 42. Sensors 40 and 42 are adapted to detect handholes, if any, in the longer side wall 44 of a carton 44. In this situation, if a handhole is detected, this identifies that specific carton as a 12-pack which has a bottom made of relatively thin paperboard. If no handhole is detected, then the carton must be a 24-pack, where the handholes are on the end or short walls, which has a bottom made of relatively thick corrugated board. The blade 20 and its edge 22 is maintained for example at the height required for 24-packs. Consequently, if a 12-pack is detected, then the table 18 will need to be raised or lowered to reduce height “h” to the level optimum for thinner bottomed 12-packs.

[0024] Detection of which of the two types of carton a specific carton is made a distance upstream from the saw station. Consequently, when sensor 42 detects a case and sensors 38 and 40 detect a hole, a signal is send to raise table 18 after a length of time determined by an encoder. This depends on a number of factors such as the conveyor 20 speed; distance from the inspection station to the saw station 10; etc. and is readily calculated for each specific conveyor line situation.

[0025] Table 18 is carried by brackets 46 which are mounted on beam 48 which itself is support on pneumatic pistons. 50 associated with cylinders 52. Cylinders 52 are supplied with plant compressed air via lines 54. The cylinders are activated to raise the table by a simple controller (not shown) in response to the delayed signal from the sensors 40 or 42. The table 18 adjusting pneumatic system receives a constant stream of actuating signals from the sensors 40 or 42 and adjusts the table 18 or maintains it as is depending on each signal. Obviously, if only one type of carton, say 24's are being handled, the table 18 will not move at all following it being set for that carton size.

[0026] Turning to FIG. 5, this illustrates in detail the problem being addressed by the present invention. A carton generally designated 56 having a base 58 and one bottle 33 of the complement of bottles in the carton are shown sitting on carton support table 18. Bottle 33 has a main cylindrical body 34 (shown in part), a base 38 and a configured heel 36. Laterally and vertically spaced from table 18 are band saw blade 20 and associated dead plate 24. The vertical distance between table 18 and saw blade 20 is termed “cutting height” and is indicated as “h” in FIG. 5. As will be appreciated, the optimum height “h” is one wherein saw blade 20 would, when it had cut through carton side wall 34, pass along a plane parallel to and immediately above carton base 58. An elongate slot 60 is provided between saw blade 20 and table 18 into which the base 58 as it is severed by saw 20, commences entering and, when totally severed from all from side walls of the carton, falls totally into and is collected. During that action, bottle 33 and the other bottles in the carton together with the bottomless carton ride up and onto dead plate 24 and, since they are pushed and urged continuously by the next carton (not shown), continue onward to exit conveyor 16. It should be noted that the saw blade 20 contacts the radial heel 36, if at all, generally most at its lower part and not at its middle part or thereabove. If the saw 20 strikes the heel higher than the centre of the bulge 36 not only is there a real risk of damage to the bottle 33 up to breaking it open but also the saw can be damaged and consequently have a shorter useful life etc. Moreover, a shutdown of the line is most probable and, but not least, there are possible health risks of broken glass despite a “box” or cage being positioned around the saw station to minimize the broken glass risk and also to cut down on the noise generated.

[0027] In any event the present invention ensures that the correct cutting height “h” is used notwithstanding the different thickness of base 58 of the different types of cartons being handled, especially since on most occasions, the cartons being handled are not of one type and consequently, bases of different thicknesses have to be dealt with.

[0028] The 24-packs are made of relatively thick corrugated board which results in a relatively “thick” carton base or bottom which requires the saw blade 20 to be set a certain predetermined height above table top 18. However, a 12-pack carton is made of relatively “thin” paperboard which means that the blade 20, if maintained at the optimal height for 24-packs, could strike the bottles over the bottle heel and chip the bottles resulting in leakers or weakened bottles which could subsequently explode upon being refilled. 

1) A cutting device for a recycling system wherein bottles are removed from a carton having walls and a base, the device comprising means to transport bottle-filled cartons to a saw station which station includes in combination blade means and a carton support, said blade means being located above and latterly across a travel path of said carton through said station and the support being located adjacent to a cutting edge of said blade means, adjusting means to vary the vertical distance between said cutting edge and an adjacent edge of the support to cause part of said walls contiguous to said base to be presented to said cutting edge for cutting to allow severing of the base therefrom. 2) A device according to claim 1 wherein said support is generally horizontally located and parallel to said cutting edge. 3) A device according to claim 1 wherein said adjusting means adjusts the height of the support relative to the saw blade. 4) A device according to claim 1 wherein said blade means is a band saw. 5) A device according to claim 1 which said adjusting means is adapted to automatically adjust and set said vertical distance in response to an instructing signal. 6) A device according to claim 5 which includes sensing means adapted to identify a type of carton being transported to said cutting edge and, following such identification, provide instructions to vary said height where deemed necessary. 7) A device according to claim 6 wherein said sensor is adapted to sense the presence or absence of a handhole in a passing carton and, in response thereto adjusts the said height if required. 8) A device according to claim 1 wherein there is a slot between the edge of said support means and saw cutting edge which slot is adapted to allow any severed carton base to pass therethrough. 9) A device according to claim 6 wherein said sensing means is located upstream of said saw means station and is adapted to delay said instructing signal until the carton requiring a change in said height has reached the saw blade station. 10) A device according to claim 1 wherein said adjusting means is a fluid operated piston and cylinder arrangement. 